/** Servlet GET request: handles event requests. */
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Event event = null;
try {
// Event parm identifies event type from the client
String eventType = Servlets.getParameter(request, P_EVENT);
// Always must have an event type
if (eventType == null) {
Log.warn("Pushlet.doGet(): bad request, no event specified");
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No eventType specified");
return;
}
// Create Event and set attributes from parameters
event = new Event(eventType);
for (Enumeration e = request.getParameterNames(); e.hasMoreElements(); ) {
String nextAttribute = (String) e.nextElement();
event.setField(nextAttribute, request.getParameter(nextAttribute));
}
} catch (Throwable t) {
// Error creating event
Log.warn("Pushlet: Error creating event in doGet(): ", t);
response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
return;
}
// Handle parsed request
doRequest(event, request, response);
}
/** Generic request handler (GET+POST). */
protected void doRequest(
Event anEvent, HttpServletRequest request, HttpServletResponse response) {
// Must have valid event type.
String eventType = anEvent.getEventType();
try {
// Get Session: either by creating (on Join eventType)
// or by id (any other eventType, since client is supposed to have
// joined).
Session session = null;
if (eventType.startsWith(Protocol.E_JOIN)) {
// Join request: create new subscriber
session = SessionManager.getInstance().createSession(anEvent);
String userAgent = request.getHeader("User-Agent");
if (userAgent != null) {
userAgent = userAgent.toLowerCase();
} else {
userAgent = "unknown";
}
session.setUserAgent(userAgent);
} else {
// Must be a request for existing Session
// Get id
String id = anEvent.getField(P_ID);
// We must have an id value
if (id == null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No id specified");
Log.warn("Pushlet: bad request, no id specified event=" + eventType);
return;
}
// We have an id: get the session object
session = SessionManager.getInstance().getSession(id);
// Check for invalid id
if (session == null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "Invalid or expired id: " + id);
Log.warn("Pushlet: bad request, no session found id=" + id + " event=" + eventType);
return;
}
}
// ASSERTION: we have a valid Session
// Let Controller handle request further
// including exceptions
Command command = Command.create(session, anEvent, request, response);
session.getController().doCommand(command);
} catch (Throwable t) {
// Hmm we should never ever get here
Log.warn("Pushlet: Exception in doRequest() event=" + eventType, t);
t.printStackTrace();
response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
}
}
/** Servlet POST request: extracts event data from body. */
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Event event = null;
try {
// Create Event by parsing XML from input stream.
event = EventParser.parse(new InputStreamReader(request.getInputStream()));
// Always must have an event type
if (event.getEventType() == null) {
Log.warn("Pushlet.doPost(): bad request, no event specified");
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No eventType specified");
return;
}
} catch (Throwable t) {
// Error creating event
Log.warn("Pushlet: Error creating event in doPost(): ", t);
response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
return;
}
// Handle parsed request
doRequest(event, request, response);
}